Outlook for Mobile (Android?) - "Unable to update event" when trying to change appointment

We've received multiple tickets regarding the error in the subject.

We have On-Prem Exchange 2016 but can't reproduce the error with an alternative Mail App (Standard GMail App.

I've also found a public report from 4 days ago stating that using Outlook for Mobile gives the same error while using it with a GMail account (https://support.google.com/calendar/thread/259312857/can-t-edit-google-calendars-from-outlook-on-android?hl=en).

Since I haven't found any leads in here regarding this issue I'll open a new post.

App version (Android): 4.2405.2 (32405820)

Account on: Exchange 2016 On-Prem (no Hybrid) fully patched CU23 Nov23SU

Tried to reset the account on the android device but the behavior didn't change after that.

Sync itself works fine - the created appointments display in OWA about 1-10s after creating them and also when creating them in OWA it displays on the Android device after 1-10s.

Changing the appointment in OWA get synced to the Android device.

Changing the appointment in any way (start/end time, date, description/body, inviting people, change of reminder settings, (un-)setting the private flag) on the Android device gives the error "Unable to update event".

Deletion and creation of appointments on the Android device is possible.

Does anyone have any idea what broke, when it broke and how (if possible) to fix it?

My guess is that there's nothing we (users/admins) can do. Possibly a downgrade of the app (sideloading via MDM).

There have been about 5 new versions of the app in the last 10 days.